2004 VMAX HPDI 175hp overheats at idle

[dcaler]

Has always run like a dream. Did a garden hose flush, only clean water (no crap) came out the pee hole. I have changed both thermostats, the pressure relieve (poppet) valve, and the impeller. With garden hose and muffs on, it does not pee water and overheats (and beeps) after about 5 minutes at idle. What else could this be?

I DID notice that when I replaced the impeller that there was a small gap between the plastic impeller cover/housing and the metal plate. I got just the impeller and metal cup kit, and not the kit with the new plastic cover. I also noticed that the original plastic cover had a lot of hardened sealer between the cup and the plastic cover. I could not remove the hardened sealer from the cover and think that might be why I have the small gap between the cover and the plate. Does the impeller have the be perfectly tight in order to work properly, create water pressure, and make the engine pee?

[javelin90]

Impeller needs to fit perfect. Make sure that the plastic housing is not warped with a straight edge. Also if running on a hose make sure that the water runs for about 4 mins then start. I did not do this before and on muffs it got hot. Take a metal clothes hanger and push gently on the pee hole opening.
At idle depends i have seen from 3 to 5 psi at idle.
Keep us posted.

[ifishinxs]

Did you hook the hose back up when you installed the impeller? When hooked to the hose without the motor running water should come out the tell tale. The post above covered everything else.

[Ranger-85]

should not be a gap between the impeller and cup in fact should have to force cup into impeller to get it on . maybe you have wrong impeller ????

[Ballengee]

Not sure I can explain clearly but did you make sure the impeller was "bent" the correct way for the direction it turns?

[Bass Junkie]

The impeller should be such a tight fit into the housing that you must twist it to bend the fins for it to fit. If it did not fit that way you have the wrong impeller. Put a little dishwasher liquid on the fins to slick them up and twist it as you put it in. You also have to make you twist it the correct direction, the same direction as the shaft turns during operation.

[dcaler]

Thanks all. Ran the boat this weekend, no overheats. It peed fine, at idle and at WOT. That said, I never let it idle too long (and at idle is the only time it ever overheated). Reading the replies and looking back....I think I've done everything correctly, but... I believe that the bad fitting plastic impeller cover is due to the large amount of hardened Yamabond #4 that they put between the cup and the housing at manufacturing. There was more there than I expected, some was blocking, a bit, the water exit passage. I think my new cup just could not fit perfectly in the old housing. There was no way for me to remove all of that hardened Yamabond. So......I ordered the FULL fit that comes with a new plastic housing. It arrives this week and, based on my last impeller change, I think that I can do this next one with my boat IN the water. It is on a hoist and the water is only waist deep (and my stronger Son will be visiting this weekend...he doesn't know that he'll be helping me with impeller change :)
I'm pretty confident that I'll fix my impeller problem. What I am NOT confident of is is this is source of my occasional overheat at idle (if you recall, I changed both stats and the poppet valve also). Fingers crossed....more later.... (thank you all!!!)

[Ranger-85]

LOL good luck , Water still cool ???

[dcaler]

still cool water, mid to low sixties, but still warmer water than when it overheated on the muffs (but, while on the water, I am not allowing myself to idle for too long) :)

[reelmin5]

Unless you have the specific hpdi muff kit, it will overheat at idle

[dcaler]

I did not know there was a specific HPDI muff kit. Can you identify or point me to the part number? Thank you!

[Texas Larry]

This one fits my VZ200TLR with the low water pickup on the sides of the housing.



MAR-FLUSH-ER-VF RED FLUSHER/VF&VZ GE (Yamaha Motor) $86.88 @ boats.net

https://www.boats.net/product/yamaha...SAAEgKsCvD_BwE

[Ballengee]

This one fits my VZ200TLR with the low water pickup on the sides of the housing.

MAR-FLUSH-ER-VF RED FLUSHER/VF&VZ GE (Yamaha Motor) $86.88 @ boats.net

https://www.boats.net/product/yamaha...SAAEgKsCvD_BwE

Wow this is good to know. I just bought a boat with an '04 250 HPDI. I will have to get that. Thanks for the info. (Even thought this isn't a thread I started)